活化烧结法板状氧化铝的研制

本文扼要阐述了应用红外吸收光谱仪检测为主要手段开展对活化烧结法板状Ａｌ２Ｏ３的研究，证实采用高纯、超细、活性原料制取板状Ａｌ２Ｏ３可大大降低烧成温度，不仅解决超高温烧成的技术难题，而且可显著节约能耗降低成本，产品质量也符合要求。     

板状氧化铝增强氧化铝陶瓷

采用控制氧化铝显微结构的方法,通过向氧化铝材料中引入不同粒径的板状氧化铝颗粒,同时采用超细粉为初始原料来改善氧化铝陶瓷的力学性能。氧化铝试样于1550℃和1600℃下烧成并加入MgO和Y2O3来抑制晶粒的过分长大。实验结果表明：加入板状氧化铝颗粒后,氧化铝材料的抗折强度得到明显提高。     

氟化铝对氧化铝烧结性能的影响

介绍了ＡｌＦ３的加入对烧结Ａｌ２Ｏ３的体积密度、气孔率的影响,以及ＡｌＦ３对板状氧化铝形成的作用     

CuO+TiO2复相添加剂对氧化铝陶瓷烧结性能和显微结构的影响及其烧结动力学分析

研究了CuO＋TiO2复相添加剂对氧化铝陶瓷烧结性能，显微结构的影响以及形成液相时氧化铝陶瓷烧结动力学。添加剂的加入极大的促进了氧化铝陶瓷的烧结。当CuO与TiO2质量比为1：2的时候，氧化铝样品致密度最高。液相含量对致密度有明显影响，液相含量越高，烧结速率越快。添加剂的存在使氧化铝晶粒细化，晶粒形貌为等轴状。利用等温烧结的实验方法研究了烧结动力学，结果表明，是由氧离子和铝离子的扩散作用控制了烧结过程。     

液相烧结氧化铝陶瓷及其烧结动力学分析

研究了CuO TiO2复相添加剂对Al2O3陶瓷烧结性能、显微结构的影响以及添加剂形成液相时Al2O3陶瓷的烧结动力学.结果显示:添加剂的加入明显地促进了Al2O3陶瓷的烧结致密度.添加剂含量对致密有明显影响,含量越高,烧结速率越快.当添加剂(CuO TiO2)为2%(质量分数),CuO/TiO2质量比为1/2时,Al2O3样品致密度最高.添加剂的存在使Al2O3晶粒发生较快生长,晶粒形貌为等轴状.通过等温烧结动力学,确定掺杂Al2O3陶瓷烧结激活能为25.2kJ/mol,表明可能是氧离子和铝离子在液相中的扩散作用控制了烧结过程.     

电熔法板状刚玉与ALCOA板状氧化铝的比较

对电熔法板状刚玉与ＡＬＣＯＡ板状氧化铝及电熔白刚玉用作基质配料时对产品抗折强度及抗热震性的影响进行了对比研究。     

板状氧化铝和电熔法板状刚玉的晶体形貌

ＡＬＣＯＡ板状氧化铝和电熔法板状刚玉系具有板片状晶体形貌的α－Ａｌ２Ｏ３多晶集合体──具有裂理面的聚片双晶     

工艺参数对氧化铝陶瓷烧结性能和显微结构的影响

讨论了工艺参数对氧化铝陶瓷致密化行为和显微结构的影响。通过控制工艺参数,如粉料的粒径和粒度分布、生坯密度、温度机制等可以改善烧结性能、改变显微结构。     

Tabular氧化铝的显微结构

用光学显微镜、扫描电镜、能谱仪和衍射仪研究了Ｔａｂｕｌａｒ氧化铝的显微结构。借用一些显微照片解释了刚玉和β－Ａｌ２Ｏ３结晶形貌的细节。特别描述了刚玉表面的台阶生长形貌。     

板状氧化铝的生产、特性及应用

介绍了美国Ａｌｃｏａ公司板状氧化铝的生产工艺、理化特性及其在钢铁工业中的应用。     

Tabular氧化铝的再热沿晶开裂

ＡｌｃｏａＴａｂｕｌａｒ氧化铝部分晶体异常长大，达４０～６００μｍ。当再热处理时，这些晶体将发生沿晶开裂现象。借助于ＯＭ和ＳＥＭ研究了裂纹的走向和尺寸。     

用烧结刚玉研制再结合刚玉砖

介绍了以烧结刚玉和板状刚玉为原料试制再结合刚玉砖的生产工艺。同时，研究了不同原料、氧化铝微粉、外加物及工艺条件对制品性能的影响。     

Erosion mechanism of tabular alumina of various microstructures under different basicity of blast furnace slag

In this study, three types of commercial tabular alumina aggregates with different microstructural characteristics were selected for corrosion tests on blast furnace slags with varying basicities. A corrosion mechanism with different microstructural characteristics is proposed, and the dominant microstructures in high- and low-basicity environments are evaluated. The pore structure was found to have a crucial influence on the dissolution of tabular alumina aggregates in the blast furnace slag. Under low-basicity (0.5–0.7) conditions, a small amount of clustered pore structure was beneficial for obtaining the maximum thickness (40–60 μm) of the isolation layer between the tabular alumina aggregate and slag. Under high-basicity (0.9–1.1) conditions, the circular pore structure tended to form a uniform and stable double-layer isolation structure of calcium hexaaluminate and MgAl₂O₄ spinel.     

Preparation of tabular corundum aggregate from different sources alumina raw powder: Sintering kinetics and establishment of kinetics model

In this paper, we report the use of four types of commercial alumina raw powders as raw materials for the preparation of tabular corundum aggregates under the same conditions. The influence of the transition phases of alumina raw powder on the sintering kinetics of tabular corundum is discussed, the sintering model of materials with pseudomorphic structure is established, and the mechanisms underlying the different performances of various commercial tabular corundum samples are evaluated. The following conclusions were drawn based on the results of the study. (1) A double tetrakaidecahedron model was established and was shown to satisfactorily describes the sintering mechanism of alumina raw powder with pseudomorphic structure, which accords with the porosity change trend of sintered body and provides a basis for perfecting the sintering theory. (2) Compared with the other transition phases, γ-Al₂O₃ shows the largest phase transformation volume contraction, which provides the driving force for the sintering process via an increase in surface energy and mainly acts in the densification and grain growth stages. Thus, high-quality refractory raw materials are prepared with optimized physical properties and Intracrystalline pores or pore clusters in the crystal structure. The preparation of these high-quality refractory products is of importance for prolonging the life of these materials and also meeting rising energy demands.     

电熔法板状刚玉的技术开发

采用电熔工艺可以生产出以α－Ａｌ２Ｏ３为主晶相的板状刚玉。其理化指标如下：Ａｌ２Ｏ３９９．１１％，ＳｉＯ２０．０７％，Ｆｅ２Ｏ３０．０４％，Ｎａ２Ｏ０．２３％，颗粒体积密度３．８９ｇ／ｃｍ３。     

Microstructure and mechanical behavior of TiO2-MnO-doped alumina/alumina laminates

Tapes of TiO₂-MnO-doped alumina (d-Al₂O₃) and pure alumina (Al₂O₃) were shaped via tape casting. Laminates with three different layer numbers and respective thicknesses were produced and sintered at 1200°C. The microstructure and mechanical behavior of laminates were investigated and compared to the respective monolithic references (d-Al₂O₃ and Al₂O₃). The use of dopants in alumina decreased the initial sintering temperature, leading to higher densification at 1200°C (~98% theoretical density (TD)) when compared to Al₂O₃ (~73% TD). The higher density was reflected in a higher Young's modulus and hardness for doped alumina. A region of diffusion of dopants in pure alumina layers was observed along the interface with doped layers. The mechanical strength of d-Al₂O₃ samples sintered at 1200°C was not statistically different from Al₂O₃ samples sintered at 1350°C. The strength of laminates composed of doped layers with undoped, porous interlayers did not change. Nevertheless, as the thickness of these porous interlayers increases, a loss of strength was observed. Monolithic references showed constant values of fracture toughness (K_IC), ~2 MPa·m^1/2, and linear crack path. On the other hand, K_IC of laminates increases when the crack propagates from weak Al₂O₃ layers to dense d-Al₂O₃ layers.